The invention is based on a machine tool receptacle.
From European Patent Disclosure EP 0 904 896 A2, a grinding machine tool receptacle for a hand-held angle grinding machine is also known. The angle grinding machine has a drive shaft that has a thread on the side toward the tool.
The grinding machine tool receptacle has a slaving means and a lock nut. For mounting a grinding wheel, the slaving means is slipped with a mounting opening onto a collar of the drive shaft and braced against a bearing face of the drive shaft in the circumferential direction by nonpositive engagement via the lock nut. The slaving means has a collar, extending axially on the side toward the tool, that on two radially opposed sides on its outer circumference has recesses that extend axially as far as a bottom of the collar. From each of the recesses, a respective groove extends on the outer circumference of the collar, counter to a driving direction of the drive shaft. The grooves are closed counter to the driving direction of the drive shaft and taper axially, beginning at the recesses, counter to the drive direction of the drive shaft.
The grinding wheel has a tool hub with a mounting opening, in which two opposed tongues are disposed, pointing radially inward. The tongues can be introduced axially into the recesses and then in the circumferential direction, counter to the driving direction, into the grooves. The grinding wheel is fixed by positive engagement in the grooves in the axial direction via the tongues and by nonpositive engagement by means of the tapering contour of the grooves. During operation, the nonpositive engagement increases as a consequence of reaction forces exerted on the grinding wheel, which act counter to the driving direction.
To prevent the grinding wheel from running off center when the drive shaft is braked by the slaving means, a stopper, which is movably supported in the axial direction in an opening, is disposed in the region of a recess on the circumference of the collar. In a working position where the grinding wheel points downward, the stopper is deflected axially by gravity in the direction of the grinding wheel and closes the groove in the direction of the recess and blocks a motion of the tongue, located in the groove, in the driving direction of the drive shaft.
The invention is based on a machine tool receptacle, having a slaving device by way of which an insert tool can be operatively connected to a drive shaft; wherein the insert tool is operatively connectable to the slaving device via at least one detent element, supported movably counter to a spring element, which detent element snaps into place in an operating position of the insert tool and fixes the insert tool by positive engagement.
It is proposed that the insert tool is a circular saw blade. By means of the positive engagement, a high degree of safety can be attained, and a simple, economical, tool-less fast-clamping system for a circular saw, especially a circular power saw can be created. The circular saw blade can be securely prevented from running off center, even in the event of braked drive shafts, in which major braking moments can occur.
Because of the movably supported detent element, major deflection of the detent element can be made possible in the assembly of the circular saw blade, and as a result on the one hand a major overlap between two corresponding detent elements, and an especially secure positive engagement, can be realized, and on the other, a readily audible snap-in noise can be achieved, which advantageously tells the user that the snap-in operation has been completed as desired and that the tool is ready for operation.
The detent element can fix the circular saw blade by positive engagement directly or indirectly via an additional component, for instance via a rotatably and/or axially displaceably supported detent lever or tappet and the like coupled to the detent element. The detent element can fix the circular saw blade by positive engagement directly and/or indirectly in various directions, such as the radial direction, axial direction, and/or especially advantageously the circumferential direction. It is also possible that by the positive-engagement fixation of the circular saw blade to the detent element in a first direction, such as the radial direction, the circular saw blade is fixed by positive engagement in a second direction, for instance the circumferential direction, by means of a component separate from the detent element.
The movably supported detent element can be embodied in various forms that appear useful to one skilled in the art, for instance in the form of an opening, protrusion, peg, bolt, and so forth, and can be disposed on the circular saw blade or on the slaving device. The detent element can itself be supported movably in a component at a bearing point, for instance in a flange of the slaving device or in a tool hub of the circular saw blade. Moreover, by means of the positive engagement, an advantageous coding can be attained, so that only intended circular saw blades can be fastened in the machine tool receptacle. The slaving device can be embodied at least in part as a separable adapter part, or it can be joined inseparably to the drive shaft by nonpositive engagement, positive engagement, and/or material engagement.
The detent element can be embodied as movable in various directions counter to a spring element, for instance in the circumferential direction or especially advantageously in the axial direction, as a result of which a structurally simple embodiment is attainable.
In a further feature of the invention, it is proposed that a drive moment can be transmitted via a positive-engagement connection between the circular saw blade and the slaving device. A high drive moment can be securely transmitted, and moreover, a drive moment can be prevented from acting on a nonpositive connection.
If the detent element can be released from its detent position by an unlocking button, then independent separation of the detent connection, for instance by a braking moment, can be securely avoided, and safety can thus be enhanced. Operation of the circular saw blade in two circumferential directions can be made fundamentally possible, and the convenience upon mounting and unmounting of the circular saw blade can be increased.
It is also proposed that the circular saw blade is connectable to the slaving device via a tongue-and-groove connection, which is secured by positive engagement via at least one detent element in an operating position of the circular saw blade. With a tongue-and-groove connection, an especially space-saving, lightweight construction can be attained, in which individual components are used for multiple functions; for instance, the detent element and/or spring elements that engage grooves can be used for radial centering, fixation in the axial direction, and/or fixation in the circumferential direction.
If the circular saw blade is connected to the slaving device in the circumferential direction via at least a first element and in the axial direction via at least a second element, however, then simple and economical tool hubs can be attained, which can advantageously be embodied as flat. The tool hubs can be prevented from catching in production and storage, and good manipulation of the circular saw blade with its tool hubs can be made possible. The components can furthermore be designed advantageously for their function, that is, for either the fixation in the circumferential direction or the fixation in the axial direction. The elements can be formed by a single component or advantageously by separate components. The tool hubs can advantageously be embodied simply, with a closed centering bore, and low-vibration running of the circular saw blade can be made possible. Also, given a suitable choice of the diameter of the centering bore, it can be attained that circular saw blades intended for the machine tool receptacle of the invention can be secured to conventional circular saw blades via already-known fastening devices known, specifically via fastening devices in which the circular saw blade can be fixed by positive engagement in the axial direction and by nonpositive engagement in the circumferential direction on the drive shaft against a bearing face, using a tightening screw or tightening nut.
In a further feature, it is proposed that at least one detent element, extending in the axial direction, snaps into a recess, corresponding to the detent element, of a tool hub of the circular saw blade in an operating position of the circular saw blade and fixes the circular saw blade in the circumferential direction by positive engagement. With a structurally simple embodiment, an advantageous positive engagement in one circumferential direction and preferably in both circumferential directions can be attained. The axially extending detent element can be formed by a separate bolt or by a formed-on peg, the latter made for instance by a deep-drawing operation, and so forth.
Advantageously, at least one detent element extending in the axial direction is secured in a component supported displaceably on the drive shaft counter to the spring element. One and especially advantageously a plurality of detent elements can be well guided on the drive shaft via a large bearing area. Tilting of the detent elements and motion of the detent elements relative to one another can be avoided reliably, and with a spring element that can advantageously be disposed centrally and rotationally symmetrically, a desired spring force for a detent operation can be achieved. However, it is also possible for one or more detent elements to be embodied as displaceable, each in respective bearing points, counter to at least one spring element each, or counter to a common spring element.
It is also proposed that the slaving device has at least one fastening element, extending in the axial direction, which can be passed through at least one region of an elongated slot of the circular saw blade and in the elongated slot is displaceable in a narrower region of the elongated slot, and by way of which the circular saw blade is axially fixable in the elongated slot via a contact face disposed on the fastening element. The tool hub can advantageously be embodied economically and essentially flat and can be used as a spring element, for instance elastically deforming the tool hub upon displacement of the component in the elongated slot. The tool hub can furthermore be used to deflect a component counter to a spring element in the axial direction. Additional components and installation effort and expense can be saved as a result.
To make a long spring travel of the hub possible, advantageously a component forming a bearing face for the circular saw blade, in the fastened state of the circular saw blade, has a recess in the region of the elongated slot, into which recess part of the circular saw blade is pressed elastically, in an operating position of the circular saw blade.
If the fastening element extending in the axial direction is supported elastically displaceably in the axial direction counter to a spring element, for axially fixing the circular saw blade, on the one hand an advantageously long spring travel can be attained independently of the tool hub, and on the other, the component and the spring element can be designed in a targeted way for their separate functions. However, the fastening element can also be embodied at least in part integrally with a spring element. If a plurality of axially extending components are provided for the axial fixation, then they can each be loaded via a respective spring element or advantageously via one common spring element, so that additional components, installation effort, weight and expense can all be saved.
To achieve an advantageous centering and low-vibration running of the circular saw blade, a collar, by way of which the circular saw blade can be radially centered, is preferably formed onto a component of the slaving device that forms a bearing face for the circular saw blade. A self-contained centering face can simply be formed. Forces on the circular saw blade in the radial direction can advantageously be absorbed by positive engagement, an example being forces in the radial direction when some item is severed. Forces can be prevented from acting radially on components that are axially displaceable, thus preventing consequent damage or wear to these components. In addition, a radial play of the insert tool is reliably avoided, so that better concentricity is attainable. Instead of a collar, an indentation which the tool hub in the secured state engages with a protrusion is also fundamentally conceivable.
The circular saw blade and its tool hub can be produced by various methods that appear useful to one skilled in the art. Especially advantageously, however, in one production operation, especially a laser-cutting process, for producing an outer contour of the circular saw blade, at least one recess for the machine tool receptacle can be made in the circular saw blade or the tool hub, making economy of production time and expense possible. Furthermore, it is possible to produce the circular saw blade with its tool hub in a stamping operation.
If at least one detent element is integrally formed onto a disklike component and/or if at least two elements for fixing the circular saw blade in the axial direction are integrally formed onto a disklike component, then additional components, assembly effort and expense can be saved. Moreover, pressed connections between individual components and the resultant leak points can be avoided.
FIG. 1, a circular power saw obliquely from above;
FIG. 2, a schematic cross section taken along the line IIxe2x80x94II of FIG. 1 through a machine tool receptacle of the invention;
FIG. 3, a tool hub seen from a side remote from the circular power saw;
FIG. 4, a variant of FIG. 2;
FIG. 5, an exploded view of a variant of FIG. 4;
FIG. 6, a tool hub of FIG. 5 from a side remote from the circular power saw;
FIG. 7, a section taken along the line VIIxe2x80x94VII of FIG. 6;
FIG. 8, an unlocking button of FIG. 5 from a side remote from the circular power saw;
FIG. 9, a section taken along the line IXxe2x80x94IX of FIG. 8;
FIG. 10, a slaving element of FIG. 5 from a side remote from the circular power saw;
FIG. 11, the slaving element of FIG. 10 from the side;
FIG. 12, a section taken along the line XIIxe2x80x94XII of FIG. 10;
FIG. 13, an exploded view of a variant of FIG. 4;
FIG. 14, a section through a slaving disk of FIG. 13 with a bolt formed onto it;
FIG. 15, a side view of a sheet-metal plate of FIG. 13; and
FIG. 16, a slaving flange from FIG. 13, seen from below.